The invention relates generally to physically unclonable function (PUF) circuits. In particular, the invention relates to incorporation of a Butterfly circuit in conjunction with a Digital Clock Manager (DCM) to provide a PUF.
The United States Armed Forces require processes to render a Field Programmable Gate Array (FPGA) used in military hardware to be secure from tampering. An FPGA represents a configurable type of integrated circuit (IC) whereby the detailed logic design is programmed in after manufacturing by the customer. Selectable programming code for the FPGA can be designed so as to operate only on authorized hardware.